


Down Where It's Wetter

by Methoxyethane



Series: Single Shots of Smut [15]
Category: Voltron: Legendary Defender
Genre: Alternate Universe - The Little Mermaid Fusion, Come Inflation, Dubious Consent, Eel!Lance, Erotic Electrostimulation, Little Mermaid Elements, M/M, Plot What Plot/Porn Without Plot, Xeno, mermaid au, merman Keith
Language: English
Status: Completed
Published: 2018-04-21
Updated: 2018-04-21
Packaged: 2019-04-25 18:11:38
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,265
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14384226
Author URL: https://archiveofourown.org/users/Methoxyethane/pseuds/Methoxyethane
Summary: The youngest prince of Atlantis goes looking for the Sea Witch in hopes of turning human. He never makes it that far.





	Down Where It's Wetter

“ _ My my, little lost fish _ ,” a thin voice hissed, echoing through dense waters to seem to end up directly in Keith’s ear. “ _ And just what are you doing way out here? _ ”

Keith knew he wasn’t supposed to swim out this deep; that waters these dark were dangerous. But it didn’t matter what anyone told him, he  _ needed  _ to do this.

As the youngest prince, Keith’s life had been a boiled down soup of boredom and safety. Sheltered was one thing but they didn’t just not let him out by himself, they didn’t even have anything for him to DO now that he’d graduated all of his lessons, and Keith couldn’t stand it anymore. 

It wasn’t like he was just running away from home with no plan. He had a plan, and he had somewhere he needed to go. And that place was the  _ surface _ . Dry land called to him, and so did that handsome human he’d saved from that shipwreck…

“I’m looking for the Sea Witch Haggar,” Keith said, summoning up all his courage into that single sentence. The dark waters shifted around him, but he still couldn’t find the source of the voice with his eyes. “I… I know she has eels in this area who work for her. I came here to find someone who can take me to her.”

The voice chuckled, low and whisping in a way that cut through the water to make Keith shiver. His eyes caught movement, something huge and dark and close, but for the life of him he couldn’t pull the sight of any fish live or dead from the water; everything a huge shifting wall of darkness.  _ “And what, _ ” the voice had somehow grown closer now, like it had circled behind him. “ _ Do you think you need from that old squid? A magic spell? A love potion, maybe? _ ”

Keith swallowed, not allowing himself to look scared and desperately dart his eyes around searching for the source of his conversation. “I need legs,” he said with confidence. “I’m going up to the surface and I need her help before I can get there.”

The voice just tsked, but Keith was finally able to make out the shape of a long ribbon-like fin swirling around him, so huge and so black he had been mistaking waves of skin for the water itself. “What would you wanna go up there for,” the strange merman complained boredly, and Keith whipped around to finally be close enough to see a set of huge, razor-sharp teeth glinting at him. “All the  _ real  _ fun’s down here, don’t you know?”

He found a pair of eyes above the teeth, glowing an eerie brilliant blue that sliced through the darkness and straight into Keith’s spine. The terror and excitement swelled in his heart as he watched those electric blue eyes as they actually literally lit up, a shock of luminescence that started in his eyes and ran all the way down his back to follow what Keith could now see as the glowing blue fin of an electric eel.

Well. Guess he’d found the right place, at least.

The fear was intense and real now, but Keith was royalty and he refused to let himself waver in the face of this… predator. “Yeah, don’t think your version of ‘fun’ is the one I’m looking for,” he said firmly, locking eyes with the eel and trying not to notice how much bigger the other mer was than Keith in pretty much every physical capacity. 

The eel was still moving, slithering around Keith’s body in slow circles that forced him to spin around to maintain eye contact. The way he’d swum around Keith had left a glowing trail of his long fin behind, looping around Keith to close him in and show off exactly how much of a size difference lie between them, and exactly how likely it was for Keith to be able to swim away should he attempt an escape.

“I need to go on land,” Keith demanded. “If you’re not gonna help me, leave me alone so I can find someone who will.”

The laugh, Keith decided, was only slightly less chilling when he could see where it was coming from. “Oh you sweet little carp,” the eel sang. “No one else you meet down here is gonna even talk to you. They’ll just skip right over that part to sink their teeth into your pretty black scales.”

The waters were colder than any Keith had ever felt, although the abject terror was probably a factor. “ _ Koi _ ,” Keith nonetheless corrected in a snap. “Don’t mistake me for some common plate fish. And what do you want from me, anyway? If you’re not planning on eating me, then as far as I’m concerned we have no business.”

“You’re so  _ fiesty _ !” The eel chuckled from - behind him? It was hard to keep track, as hard as Keith may have been trying. “It’d be a waste to just chop you up, tempting as you might be~” As soon as Keith spun around to try and find the mer’s face he was already moved past, only a streak of fluorescent-bright tail in Keith’s view. 

The question Keith had on his tongue froze and clipped off into nothing, his eyes growing wide as something unseen brushed against the fin of his own tail. It wasn’t the touch itself that stopped him, of course, but the current of electricity that ran from the point of contact all the way up Keith’s spine to instantly paralyze him. Keith tried desperately to move, to swim away or thrash or lash out or even twitch, but from his fingers to his fins he could only feel a solid buzz of nothingness weighing down his useless limbs and freezing him in place.

Gleaming blue eyes were once again directly in front of him, grinning at him even more obviously than the beast’s razor teeth were. “I’m Lance, by the way,” he introduced cheerfully. “Let’s take this conversation somewhere a bit more...  _ comfortable _ .”

\--

It was a funny thing, being paralyzed. He wasn’t unconscious, but at the same time it somehow didn’t feel quite like being awake, either. The disconnect of not being able to feel his body was almost dreamlike, no sensations but the slight leftover tingle as he watched the water sweep past his unfocuses eyes. Even the terror seemed far away. 

‘Lance’ the eel didn’t even need to put forth any effort in dragging Keith off to his cove, as it were. Just tugged him along easily with one hand as they slipped through the grasses into a crevice in the reef walls that couldn’t even be seen until they were already inside.

Funnily enough, the small space of Lance’s tiny little hole was almost cheerfully bright compared to the dark waters of the deep grassy areas the eels inhabited. That was of course because the electricity from Lance’s own body was lighting it up, giving Keith a perfect blue-tinted view of the decorated walls of the eel’s home. He knew there was still a chance he’d be eaten, but somehow... Seeing his predator’s knicknack-lined shelves kind of lessened the fear a bit.

Lance was face to face with him again, grinning at Keith with self satisfaction. “Wow, you really are a pretty little koi, aren’t you?” He said with admiration, tail still half wrapped around Keith,  though no shock was passing between their contact. His eyes were curious and his hands were unabashedly large, running over Keith’s body in explorative touches that felt almost delicate on his goosepimpled skin. “Sparkling black scales and pure white skin, I’ve never seen anything so  _ soft-looking  _ before~”

His hands moved to cup Keith’s face, finally close enough to see a the sharp black tips of Lance’s fearsome nails. It should have been a reminder of status that sent fear through his being, but the gentle way those dangerous hands were holding him sent a different kind of thrill Keith could only describe as excitement trilling through his being.

Keith still couldn’t move, of course. Could only float there in Lance’s hold as the eel touched every part of his body he could reach, running fingertips through his hair and along his ear fins and over his lips just to start, every touch sending shivers down Keith’s limp spine and making his heart beat louder and harder. 

Even just his fingers were so huge, though, especially when they got to Keith’s thin neck. He was just cupping the back of Keith’s head and neck, but one hand was large enough to cover the entire span of both easily. His touch was so delicate though, like he was trying to touch everything at once without so much as leaving a bruise. 

His other hand was under Keith’s back, holding the curve of his hips where his back turned into his tail. That hand he held fast, using it to keep Keith’s body close to his own so he didn’t float off with his inability to use his own tail to steady himself while Lance explored.

When fingertips brushed against his nipples Keith gasped and Lance laughed, low and echoing in the small space. “So cute,” he crooned again in that naturally hissing voice of his, delighted as he touched Keith’s collarbones and nipples and the lines of his abs and soft belly. “I love your coloring, cute white spots all over your tail. Pure black mermaids are pretty but you’re way more interesting!”

Keith whimpered, feeling his fingers and the very tips of his fins twitching as everything else in his body  _ tingled _ . Lance had moved on to exploring his tail now, stroking the scales and the sensitive places where his fins met flesh. When cool lips were suddenly pressed right onto the gills of his left side Keith squeaked, and Lance laughed again, harder and louder than ever. 

“I think I’m starting to get you, little Koi,” Lance purred in a chuckle. “It wasn’t even really the surface world you were longing for, is it?” Two too-large hands ran up and down Keith’s sides in a gesture that felt both intimate and possessive. “You were just bored and looking for  _ excitement _ .”

Keith had a hundred objections on his tongue but none of them came out, still capable of nothing but shaking and strained whimpering. Which was of course, the natural time for the curious hands examining his torso to find the blossoming folds of Keith’s genital slit at it exposed itself for his touch. Lance cooed in delight, the press of lips against his neck turning to teeth for a the briefest moment before he was pulling back to look down at Keith’s hips where he was flowering out in wet invitation. 

“Oh my god!” Lance barked out in a laugh. “Is that your pussy? Are you seriously  _ turned on _ right now?”

His fingers rubbed deliberately over the sensitive lips of Keith’s opening, just two digits more than large enough to explore the entire length of it. “I guess I shouldn’t be surprised, considering how long you've been playing dead and pretending you can’t move when the shock wore off after a minute or two.”

“Wh-” Keith’s would-be words were cut off into loud moan as one of Lance’s fingers slipped inside, just the very tip breaching his wetness and making Keith wail and his tail thrash in the waters as he discovered he could, indeed, move once more. In the end the only words he managed were a the low curse “Oh, fuck,” as the finger continued to breach further inside to fill him up.

“Holy fuck,” Lance swore in wonder, moving his single finger shamelessly to feel Keith’s scorching cunt. “I think you might be juicier than any mermaid I’ve ever fucked before, just how horny ARE you?”

Thoughts running a mile a minute and body shaking too much to keep up with any of it, Keith only whined. Oh god fuck, how had he let this happen, what WAS happening and why did it feel so  **good** , what should he even do and god, why WAS he so wet was Keith  _ really that fucked up? _

One of Lance’s fingers was already all the way inside him, with the tip of a second playing teasingly at the slick leaking out of his entrance. Keith’s tail flipped and fluttered against Lance, slapping lightly against his own great body as Keith regained just enough control of his own limbs to claw uselessly at Lance’s arms as the second finger slipped into his pussy.

“You know,” Lance started in a low pant into Keith’s black nipples in between slaving his tongue in sloppy patterns on Keith’s chest. “I was only planning on scaring you a little bit. Teasing you and letting you escape so you’d know better than to come back.” Keith trembled, throbbing greedily around the fingers he knew in the back of his mind should probably feel a lot more like a disgusting violation than a craving being fulfilled. “But if you’re this slutty this fast, I should keep you here and give this tight little pussy the fucking it deserves, huh?”

“N-no,” Keith whined pathetically, flapping a little bit harder but still not strong enough to try and wiggle out of the eel’s grasp. “You can’t!”

Lance laughed again, fingers driving more forcefully into Keith. “You know I can feel you throbbing like that, right? The more you deny it the looser and stickier you get around my fingers.” Said fingers wiggled viciously, and Keith buried his head into Lance’s collarbone with a whimpering moan. 

The fingers were suddenly withdrawing, leaving Keith bereft with emptiness and unsure of what to do. “It’s okay,” Lance was already assuring him with a smug grin. Gills fluttering wildly against his neck trying to bring in oxygen, Keith finally opened his eyes again to see the thick writhing length of Lance’s own genitals growing eagerly out of him with a thrash. “If playing victim’s what you’re into, we can keep pretending this is only happening because you can’t get away.”

As if to prove his point Lance’s hands left Keith entirely, leaving him floating confusedly in the water for a few short seconds. When he didn’t immediately try to hurdle himself out of range Lance laughed again, his absurdly long tail lashing up from behind to press Keith’s body back against his. 

He could feel the hard tentacle-like cock that was pressing against his belly, slithering curiously as it searched for Keith’s open slit. The very tip found his opening and Keith chirped in excitement and fear, trilling as the organ stroked itself over his slick folds for just a moment before it was slipping itself enthusiastically into Keith’s waiting cunt. 

“Holy fuck, baby,” Lance swore in a pleased sigh a he rolled his own hips against Keith’s. “So tight and so hungry for me, I don’t know how I’ll be able to hold myself back.”

Oh fuck. Oh fuck this was a bad idea, he was seriously and totally getting dicked right now and it was - fuck it was too BIG, the further Lance tried to squeeze his cock inside of Keith the more it  _ hurt  _ and Keith was jerking back to try and get Lance off of him and out of him with a scared cry of, “N-no, you  _ can’t _ ! It won’t fit!”

He finally moved, finally thrashed enough to turn around and try and swim away but by then it was too late. Lance had a grip around Keith’s waist in a second, not even bothering to flip him back around before he was hauling him by the tail backwards to slide back onto his cock.

“Feels like it fits just fine to me,” Lance laughed, filling up Keith’s aching tightness with wiggle of his cock, still holding Keith by the tail as he began a series of short thrusts that stirred up Keith’s insides when Lance’s dick curled and writhed in his cunt. 

The burn of pain did lessen second by second, replaced with reluctant pleasure as Lance stretched him open with the almost gentle movements of his cock. He was letting him get used to it, Keith realized as his whimpers of fear melted into horny chirping once more. 

When the tip of Lance’s cock hit Keith’s g-spot, he truly howled for the first time that night. His eyes shot open on their own, only managing to register the clouds of dirty floating up in the waters where he was digging his nails into the sand, scratching hard lines in the earth beneath them with every thrust as Lance moved inside with with delicious unpredictability.

Once he’d found it the eel continued to aim for that spot with relentless efficiency, even as the angles in which Keith was being plundered remained constantly changing. Keith would never admit to how little time it took for him to dissolve into a pliant slutty mess, but he’d also never admit to having gotten wet for this roguish predator in the first place and here he was face down in the sand trying to hump his hips backwards to fill himself up with more dick. So. Maybe don’t trust Keith’s account of the situation.

Lance was laughing again because he was terrible, and being terrible as he was he was even gently shoving Keith’s hips off of him and pulling out. Keith whined pitifully and let himself be manhandled, turned around again to face Lance and pulled against him with one smooth yank. Face to face again Lance leaned down to plunder his mouth in a kiss, moaning into it when Keith shyly flickered his tongue back in return. 

The thick slither of Lance’s cock found it’s way back to Keith’s pussy in no time, sliding in easily as Keith rolled his hips up against Lance to help. It went deeper this time than before, as when Keith had still been more scared than turned on for a minute there, he hadn’t yet been trying to help Lance in. Now he could feel not only the entirety of the curling tentacle-like tip but also the rigid base, the smooth slimy texture turning to hard ridges that pulled and grinded against the soft slick inside’s of Keith’s cunt.

“Feeling good yet?” Lance asked into his lips with a smile, one hand reaching back to wrap around Keith’s lower back and use it to keep their bodies pressed together while they moved against one another. “Your little pussy feels like it’s having fun; you wouldn't even let me all the way inside before. Now instead it feels like you’re sucking me deeper.”

Keith keened, his arms wrapped around Lance’s broad shoulders so he had something to cling desperately as he rode Lance’s massive cock. “Yes,” he gasped out between rolling squirmy thrusts. “It’s good, it's good, I want  _ more _ .”

“More?” Lance laughed. “You’re already stuffed full and you want more?”

Keith’s answer was more of a sob than actual words, an eager nod against Lance’s collarbone half bitten down into a moan. Lance’s cock was already moving more forcefully as he increased the pace which he rocked into Keith, but he was also prying Keith’s upper body off of his own enough to be able to slide a hand between their chests. His toothy mouth moved from Keith’s lips down to his neck, still holding Keith’s ass with one big hand while curious fingers from the other slid up Keith’s chest from the dip of his belly button. 

The gentle slide of fingers brought with it an electric tingle, the slightest shock transferred skin to sensitive skin. Keith shivered as his heart jumped at the strange sensation, a new moan torn out of him as Lance paused to confirm, “Still good?”

Far beyond words and still desperately trying to ride Lance’s squirming cock, Keith attempted a nod. Lance must have caught on, but this time was at least too caught up to laugh at Keith since he was still using the one hand he had planted gropily on Keith’s ass to drop the koi onto his dick. Either way he didn’t stop any of it, fingers now painting electric trails up and down Keith’s chest, each touch seeming to send a shock through the entire surface of Keith’s body radiating from the tingling points of contact.

When Lance pinched his nipples, he ended up shocking the sensitive nerve-riddled area with a jolt so powerful that it made Keith’s entire spine go tense and his eyes roll to the back of his head. The moment he could control his body again Keith screamed in ecstasy, nails digging jagged trails into Lance’s back and shoulder blades as his tail slapped wildly against Lance’s, a desperate flopping clap of flesh on flesh that should have been the loudest thing in the small cavern space. You know, if not for Keith screaming. 

Keith’s entire body throbbed, lit up with sensations all anchored in the thick shaft of Lance’s cock, stuffed so deep and pounding so hard it didn’t even have room to keep squirming and curling against his insides anymore. Lance was saying more dirty nonsense Keith was too fucked out to comprehend, inaudible through Keith’s continued howls as he convulsed on the hard ache of dick filling him up. The ridges of Lance’s base caught on the hard pelvic bone of Keith’s entrance, locking their bodies deep so that the frantic tango of their fucking would do nothing to dislodge their union. 

Lance was also of course, fucked so deeply into Keith’s sloppy-soaked cunt that it was impossible NOT to hit his g-spot with at least some part of his dick on every thrust. It reduced Keith’s brain to nothingness, a happy mush of sex and lightning and a delicious sense of powerlessness as he could only float uselessly and get railed.

Keith’s senses were overwhelmed, overtaken by the heat and wetness and electricity. Time was nothing anymore so he didn’t know how long it went on before he registered the sound of Lance’s laughter in his ear, and this time the light buzz of the eel’s electricity did not travel through his fingertips. The jolt went instead straight through the skin of his cock, buried deep in Keith’s pussy and sending a shock right to his g-spot that for a second Keith thought might have killed him.

He wasn’t dead but he WAS coming, and  **hard** . Harder than he ever had in his life, mind washed blank and body shaking as his eyes rolled to the back of his head and his mouth dropped open in a trill so high-pitched it was actually  _ silent _ . 

He’d never had an orgasm last so long before, either. But he was still throbbing and immobile with pleasure minutes later, Lance’s hand now cradling the back of his head to his chest with the arm that wasn’t still supporting his back. Holding Keith close through his orgasm, holding him as Lance continued to work his cock in Keith’s over sensitive cunt with desperate little grunts of his own. 

“Gonna fill you up,” Lance promised in a gasp. “Fill you to the brim with my cum.” The almost-gentle way he’d been holding Keith the entire time was slipping tighter, claws digging into his scales in a way that would have hurt if everything in Keith’s body wasn’t still humming with thrilling sexy  _ goodness  _ instead. Especially at the idea of what Lance had just said…

“God, I’d love to fucking egg you, fill you up proper and get you all fucking pregnant.” The words made Keith keen and chirp again, tail flapping at a new wave of arousal. When he spoke again the words were so low they were almost a growl, teeth grazing against Keith’s gills. “...But I’m still gonna wreck this pussy so you can’t forget me anyway.”

The idea of somehow forgetting this made Keith want to laugh, if he was able to breathe right now. But Lance was sinking his teeth into the sensitive skin under Keith’s jaw and shooting a scorching hot burst of thick semen into him, fast pulses filling him so much where he was still locked in at the base of his cock that when it had no way to escape out. Keith’s entire stomach felt bloated, but in some sick delicious way that just resulted in another small orgasm from Keith just because of the pressure filling him up.

They sunk to the sea floor in an exhausted tangle of limbs, tails twined together as they lay panting. Keith was still shaking even when Lance’s cock went soft enough to retreat back to its sheath, a slide that brought with it a trail of come that floated in the water for a few moments before settling in the sand in a filthy glob.

A few dozen minutes later when Keith’s orgasm had worn off enough for him to regain proper consciousness, he was also cognizant enough to panic. The eel he was wrapped in was sluggish, maybe even dead asleep after his orgasm so there was more than opportunity to slip out of his grasp and dart to the cave’s little exit. His mind was more of a confused mess than ever after what had just happened, dear Poseidon what had Keith DONE?

He went home, all thoughts of sea witches and princes on dry land forgotten. It was not, however, the last time he would ever swim down to the cold waters of the Eel’s Grove.

It would in fact, be a pathetically short time before Keith returned.

\--

 

**Author's Note:**

> Written for my entire bottom Keith discord server (but obviously mostly Mochi) THANKS GUYS U HELP SO MUCH WITH WRITING!!!


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